1. Technical Field
The present disclosure is related to gas analysis probes as probes for gas analysis.
2. Background Information
Conventionally, exhaust combustion gas exhausted from a boiler that combusts coal or heavy oil includes components such as NOx, SOx, SO2, CO2, and CO. Constantly, the component amount is analyzed by a gas analyzer, and the result of analysis is used for control such as denitrification and desulfurization, as well as for ecological monitoring. The gas analyzer may be an open-path type and a probe-type.
The above-mentioned probe-type gas analyzer includes a tubular probe for gas analysis, which is disposed perpendicular to a pipe through which exhaust combustion gas flows, as disclosed in the specification of U.S. Pat. No. 5,781,306. The above-described probe for gas analysis will be explained hereinafter.
FIG. 10 is a schematic side view of a conventional (prior art) probe for gas analysis. A probe 200 shown in FIG. 10 has the shape of a tube, and is arranged perpendicular to a pipe 202 (e.g., gas flue). The probe 200 is formed with an opening 203A and an opening 203B respectively on an upstream side and a downstream side with respect to a flow direction of sample gas S (e.g., exhaust combustion gas). The sample gas S flowing in the pipe 202 flows into the probe 200 through the opening 203A, and flows out through the opening 203B. Accordingly, the probe 200 is filled with the sample gas S. Then, a measuring light for measuring objects is passed through a measurement field (e.g., measurement cells) formed in the probe 200, and the attenuation amount of the measuring light is used for quantitative determination of the measured objects.
However, according to the above-described probe, the opening is formed on the upstream side with respect to the flow direction of exhaust combustion gas, so the dust along with the gas component in the exhaust combustion gas flows into the probe. Particularly, when the amount of the dust is large, in the measurement cell, the dust causes absorption and scattering of the measuring light, resulting in the attenuation of the measuring light. Accordingly, the quantity of light for measurement likely cannot be obtained. In other words, the measurement accuracy may be reduced.